linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * Xen stolen ticks accounting.

 */

#include <linux/kernel.h>

#include <linux/kernel_stat.h>

#include <linux/math64.h>

#include <linux/gfp.h>

#include <linux/slab.h>

​

#include <asm/paravirt.h>

#include <asm/xen/hypervisor.h>

#include <asm/xen/hypercall.h>

​

#include <xen/events.h>

#include <xen/features.h>

#include <xen/interface/xen.h>

#include <xen/interface/vcpu.h>

#include <xen/xen-ops.h>

​

/* runstate info updated by Xen */

static DEFINE_PER_CPU(struct vcpu_runstate_info, xen_runstate);

​

static DEFINE_PER_CPU(u64[4], old_runstate_time);

​

/* return an consistent snapshot of 64-bit time/counter value */

static u64 get64(const u64 *p)

{

    u64 ret;

​

    if (BITS_PER_LONG < 64) {

        u32 *p32 = (u32 *)p;

        u32 h, l, h2;

​

        /*

         * Read high then low, and then make sure high is

         * still the same; this will only loop if low wraps

         * and carries into high.

         * XXX some clean way to make this endian-proof?

         */

        do {

            h = READ_ONCE(p32[1]);

            l = READ_ONCE(p32[0]);

            h2 = READ_ONCE(p32[1]);

        } while(h2 != h);

​

        ret = (((u64)h) << 32) | l;

    } else

        ret = READ_ONCE(*p);

​

    return ret;

}

​

static void xen_get_runstate_snapshot_cpu_delta(

                  struct vcpu_runstate_info *res, unsigned int cpu)

{

    u64 state_time;

    struct vcpu_runstate_info *state;

​

    BUG_ON(preemptible());

​

    state = per_cpu_ptr(&xen_runstate, cpu);

​